Crank shaft



June 4, 1929. BAER" 1,715,489

CRANK SHAFT Filed June 1926 INVENTOE. HLFKED BHE qrToAEIVE/s Patented June 4, 1 929. V

UNITED STAT its,

einrittindsmuiingor IBERIi Nz. GEEMA1\TY.Q

CRANK SHAFT. 1 i

v Application area: June a, 1926, Serial No. naseaana in Germany a m-1925; it

This invention relates to crank-shafts, especially for combustion e1igine's,wh iel1 are composed of crank-arms and crank-pins. Such composite crank-shafts have the disadvantage thatthe connections between the crank-arms and the crank-pins are not of suf ficientstrength in order to warrant asufficiently permanent anddurable connection, which will meet the practical requirements.

In constructions of this kind the slot and the connecting screw which serve for making the connection between the cranks and the pins areso arranged that a deformation of the bore of the crank will easily take place, when the connecting screw is drawn tight. In consequence thereof the crank pin will be gripped by theappertaining crank only on a part of its circumferential surface, while I another part of the material of the crank will be caused to move away from the crankpin and come out of proper contact therewith.

My present invention has for its object to 'do away with this disadvantage. According to my invention the said slots are arranged in tangential direction to the bore of V the crank and more particularly in such a manner, that the orifice of said slot will be positioned aboutdiametrically opposite to.

the point around which the material will be caused to be displaced when the connecting screw is being drawn tight. A further essential feature of my present invention consists therein, that the connecting screw is positionedobliquely to the said slot, so that the material of the crank will exert a force upon the crank-pin, which causes the former to be drawn around the latter in one direction only and much the same as if the former were pulled in the form of a ribbon around the latter. By reason of this the crank will be intimately laid against the crank-pin all over the circumference of the latter.

In the drawing I have represented an example of carrying my invention into effect. Fig. 1. is a longitudinal view, partly in section, of the novel crank-shaft according to.

my invention,-and Fig. 2 is a section taken on line 22 of Fig. 1. I I

The crank-shaft according to myinventlon consists, essentially of the crank-arms 1, 2, 3

and 4: and the intermediate crank members 7. 5 and v6. The crank-arms 2 and 3 are connected with the shaft part 7, by means of the conical part 8 and the nut9.

The crank pins 10, 11, 12 and 13 are fixedly secured within cylindrical bores in the crankengines,

members 5 and 6bythe use ofboltsl I. For

this purpose the cranks are provided with the slots 15, which are directed tangentially to the bores of the crank-pins-10, 11, 12 and'13.

By properly arranging the connecting bolts 14, the material of thecrank-members 5and 6 adjacent .thebores will be-"firmlydrawn aroundand relative to the crankpin's 10'and 13 in one direction only, when drawing said bolts tight, so that the surface of thebores will firmly-contact-at all pointswith the'sura face ofthecrank-pins; The bores and pins are furthermore precisely ground so that a,

rotation of the crank-members around the crankpins will be made impossible. v

The crank-shaft according to my invention .is assembled and its arms 2 and 3 properly ad usted with respectto each other and firm- 1y connected by drawing tight the'nut 9. In doingth s, care must be taken, that the pins 11 and 12 which areconnected to these two Thereupon the'crank-members- 5 and 6 are loosely placed by means of their bores upon the respective-crank-pins of the crank-arms 2 and 3, while the pins 10 and 13 of the cranks 1 and 4 respectively are introduced into theopposite bores. The ends of the crank-shaftv are now mounted in any suitable manner in cranks are in alignment with each other;

the crank casing (not shown). The cranks,

or pins 17 have the sole purpose of facilitatwhich have not yet been fastened upon their. I

ing the re-assembling of the crank-shaft after the same had been taken apart. I claim: i

1. A crank-shaft, especially for combustion comprising icrank-members and cranky-pins, said crank-members having b'ores for the reception of said crank-pins, slots pro L:

' vided withinsaid crank-members in a direc-' tion which is tangential to said bores, and] tightening screws arranged obliquely to said slots for drawing the opposed surfaces thereof towardeach other. I

2. A crank-shaft, especially for combustion engines, comprising crank-members I; and

crank-pins, said crank-members havingbores 95 of the conical plugsor pins 17. These plugs for the reception of said crank-pins, slots pro- 'vided Within saidcrank-members tangentially to said bores and at a point of: the latter.-

which is diametrically oppositeto the point around which the material of said crankmemberswill be displaced during compression of said slots, and compressive means for 7' compressing said "slots, said compressive means being adapted to act in a'direction obliquely to said slots, so as to cause'upon compression of said slots. a displacement of the material of said: crank-members following the r circumference ofsaid crank-pins,

slot for drawing the faces of said slot toward each other to thereby tighten said crankniember about said pin.

4. A crank-shaft having a bore and a slot communicating W1th said bore and extending tangentially therefrom to the periphery of;

- said crank-member, a crank-pin in said bore, and means for drawing together the mate-' rial of said cranknemberrat said: slotto effect a uniform binding actionot the wall'of said bore upon the periphery of said pin.

5. A crank-shaft having a bore and a slot communicating with said bore and extend ing' tangentially therefrom to the'peripher'y of said crank-member, a crank-pin in said bore, and means lntersectmg saidslot at an oblique angle theretofor' drawingthe faces a of said slot toward each other torthereby tighten said crank-n1ember about said pin.

In testnnony whereof I have affixed my slgnature.

ALFRED i ane-y 

